Amylase is secreted by salivary glands in the mouth, breaking down starch and glycogen into maltose. Amylase denatures in the stomach.
In extracellular duodenum, starch and glycogen are broken down by amylase from the pancreas via the pancreatic duct, into maltose.
In intracellular duodenum, maltose, sucrose and lactose and broken down by maltase, sucrase and lactase into alpha glucose, fructose and galactose.
They travel to the ileum for absorption.